Bonding Between Three-Dimensionally Printed Rebar and Three-Week-Old Conventional Concrete

Abstract

Faced with the need to investigate alternative solutions to the conventional reinforcement solution in reinforced concrete elements, this study analyzed the mechanical bonding capacity of deformed, three-dimensionally printed reinforcing bars. The test used was a test of pull-out of reinforcing bars in three-week-old concrete cylinders. The impression material for the bars was a polylactic acid thermoplastic material (PLA). Although this is a material whose tensile strength is much lower than the typical strengths of conventional steel, the actual study serves as a reference for future studies with printed bars of materials whose strengths compete with those of conventional steel, materials such as PLA printed with continuous carbon fiber (PLA-CCF). In this sense, four bars were evaluated, one with deformation dimensions in accordance with the NMX-B-457-CANACERO-2013 standard and three bars with deformation dimensions outside said standard. The practical results were verified considering a theoretical model of splitting of bars embedded in concrete. It was predicted that bars with deformation dimensions conforming to the NMX-B-457-CANACERO-2013 standard may be capable of transferring their maximum tensile strength to concrete within reasonable development lengths. In this way, a relevant reference model is generated to be developed with bars made of thermoplastic materials with strength greater than that of PLA.